Oats contain the soluble fibre beta-glucan which, according to four decades of research, can combat blood clot (thrombus) formation and lower raised blood cholesterol by up to 23% (a fall of 1% is equivalent to a 2% fall in the risk of heart disease). A medium-sized bowl of porridge daily is generally sufficient to achieve this. Oats also provide iron for a healthy brain and red blood cells; magnesium for normal heart function; zinc for normal healing, good eyesight and to combat colds and flu; the B vitamins thiamine and niacin and antioxidants, vitamin E and bioflavonoids. Oats are also used in herbal medicine for their anti-depressant effect and as a nerve tonic